business: add privacy-aware user projection

(cherry picked from commit a636192ef22ee69d792b0ca7db1c6be963be9cb2)

internal/store/memory/privacy.go

@@ -0,0 +1,75 @@
+package memory
+
+import (
+	"context"
+	"sync"
+
+	"telesrv/internal/domain"
+)
+
+type privacyStoreKey struct {
+	ownerUserID int64
+	key         domain.PrivacyKey
+}
+
+// PrivacyStore is an in-memory account privacy rule store for tests/dev mode.
+type PrivacyStore struct {
+	mu    sync.RWMutex
+	rules map[privacyStoreKey]domain.PrivacyRules
+}
+
+func NewPrivacyStore() *PrivacyStore {
+	return &PrivacyStore{rules: make(map[privacyStoreKey]domain.PrivacyRules)}
+}
+
+func (s *PrivacyStore) GetPrivacyRules(_ context.Context, ownerUserID int64, key domain.PrivacyKey) (domain.PrivacyRules, bool, error) {
+	s.mu.RLock()
+	rules, ok := s.rules[privacyStoreKey{ownerUserID: ownerUserID, key: key}]
+	s.mu.RUnlock()
+	return clonePrivacyRules(rules), ok, nil
+}
+
+func (s *PrivacyStore) SetPrivacyRules(_ context.Context, rules domain.PrivacyRules) error {
+	s.mu.Lock()
+	s.rules[privacyStoreKey{ownerUserID: rules.OwnerUserID, key: rules.Key}] = clonePrivacyRules(rules)
+	s.mu.Unlock()
+	return nil
+}
+
+func (s *PrivacyStore) ListPrivacyRules(_ context.Context, ownerUserIDs []int64, keys []domain.PrivacyKey) ([]domain.PrivacyRules, error) {
+	if len(ownerUserIDs) == 0 || len(keys) == 0 {
+		return nil, nil
+	}
+	owners := make(map[int64]struct{}, len(ownerUserIDs))
+	for _, id := range ownerUserIDs {
+		owners[id] = struct{}{}
+	}
+	keySet := make(map[domain.PrivacyKey]struct{}, len(keys))
+	for _, key := range keys {
+		keySet[key] = struct{}{}
+	}
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	out := make([]domain.PrivacyRules, 0, len(s.rules))
+	for k, rules := range s.rules {
+		if _, ok := owners[k.ownerUserID]; !ok {
+			continue
+		}
+		if _, ok := keySet[k.key]; !ok {
+			continue
+		}
+		out = append(out, clonePrivacyRules(rules))
+	}
+	return out, nil
+}
+
+func clonePrivacyRules(in domain.PrivacyRules) domain.PrivacyRules {
+	out := in
+	out.Rules = make([]domain.PrivacyRule, len(in.Rules))
+	for i, rule := range in.Rules {
+		out.Rules[i] = rule
+		out.Rules[i].UserIDs = append([]int64(nil), rule.UserIDs...)
+		out.Rules[i].ChatIDs = append([]int64(nil), rule.ChatIDs...)
+	}
+	return out
+}